chemistry atomic structure please get right

11 which of the following is atoms mass number

number of protons plus number of neutrons

number of electrons only

number of protons only

number of neutrons only

12 which of the following are charged and located within the nucleus of an atom

protons

neuttrons

electrons

protons and electrons

13 an atom has a charge of +1 in its nucleus which statement must be true in order for this atom to have no net charge

the one positive proton has no influence on the overall charge of the atom

there is one neutral neutron in the nicleus as well

there is one negatively charged electronoutside the nucleus

there is one negatively charge electron in the nucleus

14 rutherfords gold foil experiements proved the exisitence of which of the following

the neutron

the electrons outside the nucleus

the protons only

the nucleus

15 which of the following is the most massive part of the atom

nucleus

orbitals

neutrons

protons

16 an atom of strontium has at least four different isotopes what is different between an isotope of 86 Sr and an isotope of 87 Sr

the number of protons in the neucleus

the size of the nucleus

the number of electrons in the atom

the number of neutons in the nucleus

17 what is the average atomic mass of a sample of indium

114.5 amu

114.818amu

113.909amu

115.00amu

18 an atom of 14 protons and 14 neutrons what is the chemical symbol for the atom consult periodic table

19 an atom has an average atomic mass of about 24.3 amu what is the chemical symbol for the atom

20 an atom of varnadium has 23 protons how many electrons must it have if it has a net charge of O